• Nuclear Engineering and Technology
• /
• 제21권4호
• /
• pp.294-301
• /
• 1989

상하부 2개의 노외계측기, 노입구관 온도 및 제어봉 위치 신호를 이용하여 상세한 축방향 출력분포를 계산할 수 있는 APDMS프로그램을 개발하였다. 상하부 2개의 노외계측기 신호가 제어봉 위치에 의하여 결정된 제어봉 간섭계수와 노입구관 온도에 따른 온도 간섭계수에 대하여 보정된 후 노심 주변출력을 얻기 위하여 보정된 노외계측기 신호에 shape annealing matrix가 적용되었다. 노심의 상하부 경계에서의 출력을 얻기 위해서는 평균 노심출력과 주변출력과의 선형적 관계를 이용한 노심 상하부의 평균출력에 경계점 출력보정계수가 적용되었다. 축방향 출력분포가 2개의 노외계측기에 의해 계산된 상하부 평균 노심출력, 상하부 경계면에서의 출력 및 미리 계산된 노심의 중심 위치에서의 출력을 이용하여 spline approximation에 의하여 계산되었다. 연소도, 출력준위, 제어봉 위치 및 axial offset의 변화에도 불구하고 고리 3호기 4주기에 대하여 BOXER 코드와 APDMS 프로그램에 의해 계산된 축방향 출력분포의 비교는 5% root mean square 오차내에서 일치함을 보여 주었다.

• 한국식물병리학회지
• /
• 제3권3호
• /
• pp.159-163
• /
• 1987

우리나라에 발생하고 있는 뿌리혹선충의 Race를 조사하고 기후에 따른 종의 분포 및 밀도를 파악하기 위하여 3226포장에서 시효를 채취하여 Baermann's funnel법으로 선충을 추출하여 선충의 형태와 International Meloidogyne Project의 Differenctial Host Test Method로 조사하였다. 우리나라에 있어서 뿌리혹선충의 종류별 분포는 M. hapla가 중부지방에서, M. incognita가 남부지방에서 우점종을 이루었고, M. arenaria는 남부지방에서 검출율이 다소 높았으며 M. javanica는 제주와 남부해안지방을 중심으로 분포하고 있었다. 우리나라에 분포하고 있는 뿌리혹선충의 종별 Race는 M. arenaria에서 Race 1과 Race 2, 그리고 M. incognita에서 Race 1, Race 2 및 Race 3이 알려졌으며, 이 중에 M. arenaria Race 1과 M. incognita Race 3은 우리나라에서 처음으로 보고되었다.

• 전자공학회논문지B
• /
• 제33B권6호
• /
• pp.54-63
• /
• 1996

We propose a 3rd order blind equalizer that incorporates a new transform method using either square root operation ($\sqrt{x]$) or reciprocal operation (1/x) in order to transform symmetric distribution of PAM signals at the transmitter, to asymmetric one. At the receiver, either the square operation or the reciprocal operation is needed to recover the asymmetrically transformed signals to the original ones after eualization. The reslts of the computer simulation, using the new method are better than the existing transform method using natural logarithm operation by the maximum of 8 dB in MSE. In addition, as the skewness of the asymmetrically transformed distribution has small values, the performances are improved.

• The Korean Journal of Ecology
• /
• 제22권2호
• /
• pp.89-94
• /
• 1999

Thirty-day-old seedlings of tomato (Lycopersicon esculentum) were treated with different concentrations of HgCl$_2$(0. 10 and 50 $\mu$M) for up to 20 days. and the detailed distribution of Hg absorbed and its toxicity in different plant parts (roots, stems and leaves) were investigated. The accumulation of Hg in plants increased with external Hg concentrations. and Hg is strongly retained by roots. Further. Hg content in leaves was various. showing more accumulation in older leaves. Seedlings exposed to toxic levels of Hg showed not only the reduction of dry weight and length of both shoot and root. and chlorophyll levels in leaves but also the enhancement of malondialdehyde (a lipid peroxidation product) formation in all plant parts investigated. These results suggest that physiological impairment of a plant exposed to Hg may be achieved by internal distribution of Hg absorbed and Hg-induced oxidative stress in different plant parts.

• Communications for Statistical Applications and Methods
• /
• 제27권1호
• /
• pp.97-108
• /
• 2020

This paper compares several methods for estimating parameters of normal inverse Gaussian distribution. Ordinary maximum likelihood estimation and the method of moment estimation often do not work properly due to restrictions on parameters. We examine the performance of adjusted estimation methods along with the ordinary maximum likelihood estimation and the method of moment estimation by simulation and real data application. We also see the effect of the initial value in estimation methods. The simulation results show that the ordinary maximum likelihood estimator is significantly affected by the initial value; in addition, the adjusted estimators have smaller root mean square error than ordinary estimators as well as less impact on the initial value. With real datasets, we obtain similar results to what we see in simulation studies. Based on the results of simulation and real data application, we suggest using adjusted maximum likelihood estimates with adjusted method of moment estimates as initial values to estimate the parameters of normal inverse Gaussian distribution.

• Wind and Structures
• /
• 제31권5호
• /
• pp.419-430
• /
• 2020

Weibull distribution is a conspicuous distribution known for its accuracy and its usage for wind energy analysis. The two and three parameter Weibull distributions are adopted in this study to fit wind speed data. The daily mean wind speed data of Ennore, Tamil Nadu, India has been used to validate the procedure. The parameters are estimated using maximum likelihood method, least square method and moment method. Four statistical tests namely Root mean square error, R2 test, Kolmogorov-Smirnov test and Anderson-Darling test are employed to inspect the fitness of Weibull probability density functions. The value of shape factor, scale factor, wind speed and wind power are determined at a height of 100m using extrapolation of numerical equations. Also, the value of capacity factor is calculated mathematically. This study provides a way to evaluate feasible locations for wind energy assessment, which can be used at any windy site throughout the world.

• 한국측량학회지
• /
• 제33권3호
• /
• pp.145-153
• /
• 2015

This study aims to accurately estimate population distribution more specifically than administrative unites using a RK (Regression-Kriging) model. The RK model is the areal interpolation technique that involves linear regression and the Kriging model. In order to estimate a population’s distribution using a sample region, four different models were used, namely; a regression model, RK model, OK (Ordinary Kriging) model and CK (Co-Kriging) model. The results were then compared with each other. Evaluation of the accuracy and validity of evaluation analysis results were the basis RMSE (Root Mean Square Error), MAE (Mean Absolute Error), G statistic and correlation coefficient (ρ). In the sample regions, every statistic value of the RK model showed better results than other models. The results of this comparative study will be useful to estimate a population distribution of the metropolitan areas with high population density

• Wind and Structures
• /
• 제26권6호
• /
• pp.383-395
• /
• 2018

An accurate determination of wind speed distribution is the basis for an evaluation of the wind energy potential required to design a wind turbine, so it is important to estimate unknown parameters of wind speed distribution. In this paper, Gumbel distribution is used in modelling wind speed data, and alternative robust estimation methods to estimate its parameters are considered. The methodologies used to obtain the estimators of the parameters are least absolute deviation, weighted least absolute deviation, median/MAD and least median of squares. The performances of the estimators are compared with traditional estimation methods (i.e., maximum likelihood and least squares) according to bias, mean square deviation and total mean square deviation criteria using a Monte-Carlo simulation study for the data with and without outliers. The simulation results show that least median of squares and median/MAD estimators are more efficient than others for data with outliers in many cases. However, median/MAD estimator is not consistent for location parameter of Gumbel distribution in all cases. In real data application, it is firstly demonstrated that Gumbel distribution fits the daily mean wind speed data well and is also better one to model the data than Weibull distribution with respect to the root mean square error and coefficient of determination criteria. Next, the wind data modified by outliers is analysed to show the performance of the proposed estimators by using numerical and graphical methods.

• 수산경영론집
• /
• 제46권1호
• /
• pp.93-107
• /
• 2015

This study aims to analyze causalities among Hairtail prices by distribution channel using a vector autoregressive model. This study applies unit-root test for stability of data, uses Granger causality test to know interaction among Hairtail Prices by distribution channel, and employes the vector autoregressive model to estimate statistical impacts among t-2 period variables used in model. Analyzing results of this study are as follows. First, ADF, PP, and KPSS tests show that the change rate of Hairtail price by distribution channel differentiated by logarithm is stable. Second, a Granger causality test presents that the producer price of Hairtail leads the wholesale price and then the wholesale price leads the consumer price. Third, the vector autoregressive model suggests that the change rate of Hairtail producer price of t-2 period variables statistically, significantly impacts change rates of own, wholesale, and consumer prices at current period. Fourth, the impulse response analysis indicates that impulse responses of the structural shocks with a respectively distribution channel of the Hairtail prices are relatively more powerful in own distribution channel than in other distribution channels. Fifth, a forecast error variance decomposition of the Hairtail prices points out that the own price has relatively more powerful influence than other prices.

• 한국작물학회지
• /
• 제46권3호
• /
• pp.236-240
• /
• 2001

논토양의 토성에 따른 벼의 수량, 관개용수량 및 지하삼투수량의 차이를 구명코자 사양토, 식양토, 식토 등 3종류의 토성에서 1999년과 2000년 라이시미터(lysimeter) 조건에서 실험한 결과는 다음과 같다. 1. 벼의 초장과 분얼 및 쌀 수량은 토성 처리간 유의한 차이가 없었다. 2. 벼 생육기간 중 총관개용수량은 1년차에는 식양토, 사양토, 식토 순으로 각각 3,306, 2,650, 2,002 l/$m^2$ 이었고 2년차에는 사양토, 식양토, 식토 순으로 각각 5,281, 4,984, 3,968 l/$m^2$이었다. 3.벼 재배기간 중 총지하삼투수량은 1년차에는 식양토, 사양토, 식토가 각각 2,141, 1,228, 862 l/$m^2$ 이었고, 2년차에는 사양토, 식양토, 식토에서 각각 4,448, 3,833, 2,925 l/$m^2$이었다. 4. 지표면하 10cm까지의 깊이에 분포하는 벼 뿌리의 비율은 사양토 56.0%, 식양토 61.4%, 식토 72.0%로 식토일수록 표층부 분포 비율이 높았다. 5. 논토양에서 지하삼투수량은 토성의 영향도 있으나 토양 중 벼 뿌리 생장량의 영향도 있어서, 뿌리 생장량이 많았던 처리구의 지하삼투수량이 증가하는 것으로 나타났다.